JPS58166314A - Behind-aperture lens - Google Patents

Behind-aperture lens

Info

Publication number
JPS58166314A
JPS58166314A JP4852382A JP4852382A JPS58166314A JP S58166314 A JPS58166314 A JP S58166314A JP 4852382 A JP4852382 A JP 4852382A JP 4852382 A JP4852382 A JP 4852382A JP S58166314 A JPS58166314 A JP S58166314A
Authority
JP
Japan
Prior art keywords
lens
focal length
converging
object side
group
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP4852382A
Other languages
Japanese (ja)
Inventor
Shigetada Sato
重忠 佐藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pentax Corp
Original Assignee
Asahi Kogaku Kogyo Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asahi Kogaku Kogyo Co Ltd filed Critical Asahi Kogaku Kogyo Co Ltd
Priority to JP4852382A priority Critical patent/JPS58166314A/en
Publication of JPS58166314A publication Critical patent/JPS58166314A/en
Pending legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
    • G02B9/12—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only
    • G02B9/14—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only arranged + - +
    • G02B9/18—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only arranged + - + only one component having a compound lens

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

PURPOSE:To obtain a titled lens of >=60 deg. view angle, about F2.8 of which the overall length from an image face is about 1.1 times as long a composite focal distance of a lens system, by satisfying prescribed conditions, in a behind-the aperture lens constituted of 4 pieces in 3 groups or 5 pieces in 4 groups. CONSTITUTION:A titled lens is constituted of the first converging lens group being a cemented lens of a negative meniscus lens (the first lens) and a positive meniscus lens (the second lens), and the second converging lens group consisting of a negative biconcave lens (the third lens) and one or two positive lenses, in order from an object side. Also, when fIIa denotes a focal distance of the nearest face of the second converging lens group to the object side, and fII2 denotes a focal distance of the nearest face to the image side respectively, prescribed conditions (1)-(6) are satisfied.

Description

【発明の詳細な説明】[Detailed description of the invention]

近年、コンパクトカメラの普及には目覚ましいものがあ
り、明るくてコンパクトなレンズ系が望まれている。 本発明は、画角が６０°以上と広角を包括し、Ｆ２．８
程度で、像面からのレンズ全長がレンズ系の合成焦点距
離のほぼ１．１倍程度の、明るくて極めてコンパクトな
ビハインド絞り用レンズに関する。 従来より画角が６０°以上と広角を包括し、　Ｆ２．８
枚度と明るくコンパクトなビハインド絞り用レンズとし
ては、例えば特開昭５６−７５６１１号、同５６−３９
５１Ｏ号等が既に公知であるが、これらのレンズ構成は
接合レンズをレンズ系の後方に配置している。 これに対して本発明では、接合レンズをレンズ系の最前
部に配置し、軸外周辺光束の色収差の補正を容易としな
がら、適切なパワー配置と面形状を考慮する事により、
性能良好なるビハインド絞り用レンズの実現を達成した
ものである。 先ず１本発明のレンズ構成を説明すると、物体側から順
に、負メニスカスレンズ（第ルンズ）と正メニスカスレ
ンズ（第２レンズ）との接合レンズである第１収束レン
ズ群１両凹負レンズ（第３レンズ）、および１枚又は２
枚の正レンズからなる第２収束レンズ群で構成されてお
り１次の各条件を満足する３群４枚又は４群５枚構成の
性能良好でコンパクトなビハインド絞り用レンズである
。 （１）　０．９０　＜　ｆ　／　ｆ□＜１．５０（２）
　１．６００　＜　（Ｖ、　　　Ｖ２）　／　（ｖ、／
ｎ、　−ｖ、Ｉｎ２）（３）　１．５５０　＜ｆｌｎ、
　ｌ　ｆ＋、ｒｌ　＜１．７００　　、　　ｆ４．、＜
０（４）　２．００　＜ｆｌｆ、　　＜２．８０（５）
　０．３０　＜　ｆｅｚ／　Ｉ　ｆ４１　＜０．６５　
−　　　ｆ４　＜０（６）　０．９０　＜　ｆＨ／　ｌ
　ｆｒ　ｌ　＜１．５０　−　　　ｆ暫く０但し ｆ　：全系の合成焦点距離 ｆｌ：第１収束レンズ群の合成焦点距離ν２．ν、　：
各々第ルンズ、第２レンズのアツベ数 ｎｌ’　”２９　ｎ３　　：各々第ルンズ、第２レンズ
、第３レンズのｄ（ｉｎｓに対する屈折率 ｆｈ、ｓ　　：第３レンズの焦点距離 ｆ１：第ルンズの物体側の面の焦点距離ｆ４：第３レン
ズの物体側の面の焦点距離ｆ暫：第３レンズの像側の面
の焦点距離ｆ１１：第２収束レンズ群の最も物体側の面
の焦点距離 ’ｕｚ”第２収束レンズ群の最も像側の面の焦点距離 次に上記各条件について説明する。 条件（１）は、レンズ系の小型化を実現する為に必要で
ある。条件（１）の上限値を越えると、レンズ系の小型
化４こは有利であるが、正の歪曲収差の発生が大となり
、他の部分での補正が困難となる。 また条件（１）の下限値を越えると、レンズの全長が長
くなり、また周辺光量を十分に取り入れながら前玉径を
小さくする二とが困難となり、レンズ系の小型化には不
利であ゛る。 条件（２）は、レンズ系の小型化を達成する為に第１収
束レンズ群に条件（１）で限定される強い収束作用を持
たせた場合の、レンズ系全体のペッツバール和の減少を
計るように第ルンズと第２レンズの屈折率とアツベ数に
課せられる条件である。 条件（２）の下限値を越えると、第１収束レンズ群での
色消条件を満足しながら、このレンズ群で発生する正の
ペッツバール和を小さく抑え像面湾曲の増大を防ぐ二と
が困難となる。 条件（３）は、第１収束レンズ群、第２収束レンズ群で
発生する正のペッツバール和を、第３レンズで発生する
負のペッツバール和で打消し、像面湾曲の劣化を補正し
ようとするものである。条件（３）の下限値はその効果
を得る為の限界値である。 また条件（３）の上限値を越えると、第３レンズの両凹
面の発散作用が大となり１球面収差、非点収差が増大し
、他の部分での補正が困難となる。 条件（４）は、条件（１）と相補的な役割を持ち１条件
（１）を満足させながら諸収差、特に球面収差を良好に
保つ為に必要である。条件（４）の下限値を越えると、
レンズ系最前部の収束作用が弱くなり、レンズ系の小型
化の為の効果が酵くなる。また条件（４）の上限値を越
えると、レンズ系の小型化には有利であるが、負の球面
収差の発生が大となり。 他の部分での補正が困難となる。 条件（５）、　（６）は、レンズ系全体の球面収差を補
正した上で、コマ収差、非点収差、歪曲収差等の諸収差
をバランス良く補正する為に必要な条件で、二の条件外
の値では諸収差の補正のバランスが崩れ、性能を良好に
保つことが困難となる。 以上１本発明は上記各条件を満足して構成される二とに
より、明るくてコンパクトな性能良好なるビハインド絞
り用のレンズを得ることができるものである。 更に、前記第２収束レンズ群を２枚の正レンズから構成
する事は、画面中央部分から周辺部分に至るまで、高次
のコマ収差、フレアー等をよりバランス良く補正する為
に有益である。つまり、ビハインド絞り用レンズでは、
絞りがレンズ系後方に位置する為、絞り位置で軸外光束
を十分に確保する必要上から、軸外斜光束はレンズ系後
部のレンズ面の外周部分まで入射する。従ってレンズ系
後方のレンズを２枚に分割して自由度を増すことは、軸
外周辺光束の収差をより良好に補正する上で効果がある
。 以下、符号を次のように定め、本発明の実施例を示す。 ｒ・　：物体側から順に第１面の曲率半径ｄ、：物体側
から順に第ｉ番目の面間隔ｎｉ：物体側から順に第ｉ番
目のレンズのｄ−１ｉｎｅに対する屈折率 ：物体側から順に第ｉ番目のレンズのアツベ数In recent years, the popularity of compact cameras has been remarkable, and bright and compact lens systems are desired. The present invention has a wide angle of view of 60° or more, and has an F2.8 angle of view.
The present invention relates to a bright and extremely compact behind-diaphragm lens whose total length from the image plane is approximately 1.1 times the combined focal length of the lens system. The angle of view is more than 60 degrees, which covers a wider angle than before, and F2.8
Examples of lenses for behind apertures that are bright and compact include JP-A-56-75611 and JP-A-56-39.
No. 51O and the like are already known, but in these lens configurations, a cemented lens is placed at the rear of the lens system. In contrast, in the present invention, the cemented lens is placed at the forefront of the lens system, making it easy to correct the chromatic aberration of off-axis peripheral light beams, and by considering appropriate power placement and surface shape.
This achieves the realization of a lens for behind aperture with good performance. First, to explain the lens structure of the present invention, in order from the object side, the first converging lens group 1 is a double-concave negative lens (second lens), which is a cemented lens of a negative meniscus lens (first lens) and a positive meniscus lens (second lens). 3 lenses), and 1 or 2
It is a compact behind-the-diaphragm lens with good performance and has a configuration of 4 elements in 3 groups or 5 elements in 4 groups, which is composed of a second converging lens group consisting of 1 positive lenses, and satisfies each condition of the first order. (1) 0.90 < f / f□ < 1.50 (2)
1.600 < (V, V2) / (v, /
n, -v, In2) (3) 1.550 <fln,
l f+, rl <1.700, f4. ,<
0(4) 2.00 <flf, <2.80(5)
0.30 < fez/ I f41 <0.65
- f4 <0(6) 0.90 < fH/l
fr l <1.50 - f 0 for a while; however, f: Composite focal length of the entire system fl: Composite focal length of the first converging lens group ν2. ν, :
Atsube numbers nl'''29 of the 1st lens, 2nd lens, and 3rd lens respectively: refractive index fh, s for d(ins) of the 1st lens, 2nd lens, and 3rd lens, respectively fh, s: focal length of the 3rd lens f1: object of the 3rd lens Focal length of the side surface f4: Focal length of the object-side surface of the third lens f Temporary: Focal length of the image-side surface of the third lens f11: Focal length of the most object-side surface of the second converging lens group'uz'' Focal length of the most image-side surface of the second converging lens group Next, each of the above conditions will be explained. Condition (1) is necessary to realize miniaturization of the lens system. Condition (1) If the upper limit value is exceeded, it is advantageous to downsize the lens system, but the occurrence of positive distortion becomes large and correction in other parts becomes difficult.Also, if the lower limit value of condition (1) is exceeded. In this case, the total length of the lens becomes long, and it becomes difficult to reduce the diameter of the front lens while taking in sufficient amount of peripheral light, which is disadvantageous for downsizing the lens system. In order to achieve miniaturization, the first converging lens group and the second lens are designed to reduce the Petzval sum of the entire lens system when the first converging lens group has a strong converging effect limited by condition (1). This is a condition imposed on the refractive index and Atsube number of the first converging lens group.If the lower limit of condition (2) is exceeded, the positive Petzval sum generated in this lens group is Condition (3) means that the positive Petzval sum generated in the first convergent lens group and the second convergent lens group is reduced by the negative Petzval sum generated in the third lens group. This is to cancel the deterioration of field curvature by using the Petzval sum.The lower limit of condition (3) is the limit for obtaining this effect.Also, if the upper limit of condition (3) is exceeded, , the divergent effect of the biconcave surface of the third lens increases, increasing spherical aberration and astigmatism, making it difficult to correct in other parts. Condition (4) plays a complementary role to condition (1). It is necessary to maintain various aberrations, especially spherical aberration, in good condition while satisfying condition (1).If the lower limit of condition (4) is exceeded,
The convergence effect at the forefront of the lens system becomes weaker, and the effect of miniaturizing the lens system becomes less effective. If the upper limit of condition (4) is exceeded, it is advantageous for downsizing the lens system, but negative spherical aberration will increase. Correction in other parts becomes difficult. Conditions (5) and (6) are necessary conditions to correct various aberrations such as coma, astigmatism, and distortion in a well-balanced manner after correcting the spherical aberration of the entire lens system. If the value is outside the range, the balance of correction of various aberrations will be lost, making it difficult to maintain good performance. The present invention satisfies each of the above conditions and is configured to provide a lens for behind aperture that is bright, compact, and has good performance. Furthermore, configuring the second converging lens group from two positive lenses is useful for correcting high-order comatic aberrations, flare, etc. in a more balanced manner from the center to the periphery of the screen. In other words, with a lens for behind aperture,
Since the diaphragm is located at the rear of the lens system, it is necessary to secure a sufficient amount of off-axis rays at the diaphragm position, so that the off-axis oblique rays enter the outer peripheral portion of the lens surface at the rear of the lens system. Therefore, increasing the degree of freedom by dividing the lens at the rear of the lens system into two parts is effective in better correcting the aberration of the off-axis peripheral light beam. Hereinafter, embodiments of the present invention will be described using the following symbols. r: radius of curvature d of the first surface in order from the object side, : i-th surface spacing ni in order from the object side: refractive index for d-1ine of the i-th lens in order from the object side: Atsube number of i-th lens

【実施例１】 ｆ＝１００　　　　Ｆナンバー１　：　２．８０画角２
ω＝６２．４” ｒ、　　　３５．７１９　　ｄ、　　２．２８６　　ｎ
、１．８０５１８　　ｙ、２５．４ｒ　　　２６．５５
０　　ｄ、　１３．８８６　　ｎ２１．８３４８１　　
？、　４２．７ｒ　３　　５１−４８０　　ｄ　３　３
−８６４ｒ　　−１３４，８０３ｄ４２．２８６　　ｎ
、１．７２１５１　９３２９．２斗 ｒ、、　　　３１．５５７　　ｄ、　　１．０９８ｒ４
　　４５−６６９　　ｄｂ　１８−１５７　　ｎ４１−
８０７４０　９４３５−４ｒ　　−８４，５３９ 全長（像面から）　１１３．８ ｆ／ｆ□：１．０８ （ｖ、　−ｖ、）／　（ｖ、／　ｎ、　−ｙ、／　ｎ、
）　＝　１．８８０ｆ　／　ｎ３１　ｆ、、、　Ｉ　＝
　１．６４８　　　ｆ　／　ｆＩ＝２−２５ｆｉｚ／’
　ｌ　ｆ４１　＝０．５６　　　　ｆｌ＋／　ｌ　ｆｚ
　ｌ　＝１．２９[Example 1] f=100 F number 1: 2.80 angle of view 2
ω=62.4” r, 35.719 d, 2.286 n
, 1.80518y, 25.4r 26.55
0 d, 13.886 n21.83481
? , 42.7r 3 51-480 d 3 3
-864r -134,803d42.286 n
, 1.72151 9329.2 tor,, 31.557 d, 1.098r4
45-669 db 18-157 n41-
80740 9435-4r -84,539 Total length (from image plane) 113.8 f/f□: 1.08 (v, -v,)/ (v, / n, -y, / n,
) = 1.880f / n31 f,,, I =
1.648 f/fI=2-25fiz/'
l f41 =0.56 fl+/ l fz
l=1.29

【実施例２】 ｆ＝１００　　　　Ｆナンバー１　：　２．８０画角２
ω＝６３．１＠ ｒ、　　　３６．１５７　　ｄ、　　２．２８６　　ｎ
、１．７６１８２　　ｖ、２６．６ｒ、　　　２２．０
７５　　ｄ２１２．４５４　　ｎ２１．８３４８１　　
ｖ、　４２．７ｒ　　　５２．３０３　　ｄｘ　　３．
９２１ｒ４−１４２．６３６　　ｄ＋　２．２８６　　
ｎ３１．７２０００　　’１１３４６．０ｒ、　　　３
０．５４８　　ｄｙ　　１．３５１ｒ、　　　４５−６
４９　　ｄ４１８−１９４　　ｎ４１−７７２５０　　
νｑ　４９−７ｒ　　−７８，８８０ 全長（像面から）　　１１４．３　− ｆ／ｆ工＝１．１４ （ｖ、　−ｖ、）／　（ｖ、Ｉ　ｎ、　−９，／　ｎ、
）　＝　１．９７０ｆ　／ｎ、Ｉ　ｆｚ、ｓ　Ｉ　＝１
．６７３ｆ／ｆ、　＝２．１１ ｆｕ□／　ｌ　ｆ、　ｌ　＝０．５２ ｆ、、　／　ｌ　ｆ、　Ｉ　＝１．３９[Example 2] f=100 F number 1: 2.80 angle of view 2
ω=63.1@r, 36.157 d, 2.286 n
, 1.76182v, 26.6r, 22.0
75 d212.454 n21.83481
v, 42.7r 52.303 dx 3.
921r4-142.636 d+ 2.286
n31.72000 '11346.0r, 3
0.548 dy 1.351r, 45-6
49 d418-194 n41-77250
νq 49-7r -78,880 Total length (from the image plane) 114.3 - f/f = 1.14 (v, -v,)/ (v, I n, -9,/n,
) = 1.970f/n, I fz, s I =1
．． 673f/f, =2.11 fu□/l f, l =0.52 f,, /l f, I =1.39

【実施例３１ ｆ＝１００　　　　Ｆナンバー１　：　２．８６画角２
ω＝６２．２゜ ｒ、　　　３５．５０４　　ｄ、　　３．１４３　　ｎ
、１．８０５１８　　ｖ、２５．４ｒ、　　　２４．３
０４　　ｄ２１１．６３８　　ｎ、　１．８０４００　
　ｖ、　４６．６ｒ、　　　６１．１６５　　ｄ３　３
．５６８ｒ４−１３５．８４８　　ｄ、　２．１２４　
　ｎ３１．５４８１４　　ｖ、　４５．８ｒｓ　　　２
６．８１９　　ｄｙ　１．０４ｇｒｂ　　３５−２５５
　　ｄ４４−１０６　　ｎ４１−７１３００　　ν４５
３−８ｒ７５８−４７５　　ｄｑ　３−８５１ｒ、　　
１２１．７６３　　ｄＢ　５．９４７　　ｎ、１．７１
３００　　ｖｔ５３．８ｒｔ　　　８８−１２２ 全長（像面から）　　１０８．７ ｆ／ｆ□＝１．１９ （ｖ、−ν２）／（Ｖ、／　ｎ、　−ｖ２／　ｎ、）　
＝　１．８０３ｆ／ｎ３Ｉ　ｆ４．、ｌ　＝１．５８８
　　　ｆ／ｆ、　＝２．２７ｆＩ１２／Ｉｆ４１＝０．
５０　　　ｆｌ、／Ｉｆ５１＝１．０１【実施例４】 ｆ＝１００　　　　Ｆナンバー１　：　２．８０画角２
ω＝６３．３゜ ｒ、　　　３２．１９１　　ｄ、　　２．２８６　　ｎ
、１．８４６６６　　ｖ、２３．９ｒ、　　　２５−５
４３　　ｄｘ　１１−９５３　　ｎ、　１−７１３００
　　シュ５３−８ｒ、　　　７０．８８４　　ｄ３３．
６３５ｒ４−１５７．２６５　　ｄ４２．１４３　　ｎ
３１．５１１１８　　ｖ、　５１．Ｏｒ、　　　２３．
７４１　　ｄｓｌ、６０２ｒ、　　３０．１９９　ｄ６
４．２１１　ｎ４１．６２０４１　ｖ、６０．３ｒｔ　
　　４６−９７７　　ｄワ４−６１９ｒ、　　１２４．
４１８　　ｄｒ　４．９９６　　ｎ、１．６９＋００　
　ｖ、、５４．８ｒｌ　　−８７，５７５ 全長（像面から）　　１０８．２ ｆ　／　ｆ、　＝　１．３０ （ν、　−９，）バｖ、／ｎ、　−ｖ、Ｉ　ｎ、）　＝
、１．６１９ｆ　／　ｎ、ｌ　ｆ４．ｙ　Ｉ　＝１．６
４６　　　ｆ　／　ｆｌ　＝２．６３ｆ□２／Ｉｆ４１
＝０．４１　　　　ｆ−ＩＬ、／Ｉｆ、ｌ＝１．０５[Example 31 f=100 F number 1: 2.86 angle of view 2
ω=62.2°r, 35.504d, 3.143n
, 1.80518 v, 25.4r, 24.3
04 d211.638 n, 1.80400
v, 46.6r, 61.165 d3 3
．． 568r4-135.848d, 2.124
n31.54814 v, 45.8rs 2
6.819dy 1.04grb 35-255
d44-106 n41-71300 ν45
3-8r758-475 dq 3-851r,
121.763 dB 5.947 n, 1.71
300 vt53.8rt 88-122 Total length (from image plane) 108.7 f/f□=1.19 (v, -v2)/(V, / n, -v2/ n,)
= 1.803f/n3I f4. , l =1.588
f/f, =2.27fI12/If41=0.
50 fl, /If51=1.01 [Example 4] f=100 F number 1: 2.80 angle of view 2
ω=63.3°r, 32.191d, 2.286n
, 1.84666 v, 23.9r, 25-5
43dx 11-953n, 1-71300
Shu53-8r, 70.884 d33.
635r4-157.265 d42.143 n
31.51118 v, 51. Or, 23.
741 dsl, 602r, 30.199 d6
4.211 n41.62041 v, 60.3rt
46-977 dwa 4-619r, 124.
418 dr 4.996 n, 1.69+00
v,,54.8rl -87,575 Total length (from image plane) 108.2 f / f, = 1.30 (ν, -9,) v, /n, -v, I n,) =
, 1.619f/n, l f4. y I =1.6
46 f / fl =2.63f□2/If41
=0.41 f-IL,/If,l=1.05

【図面の簡単な説明】[Brief explanation of the drawing]

第１図、第３図、第５図および第７図は各々実施例１．
実施例２．実施例３および実施例４のレンズ断面図。 第２図、第４図、第６図および第８図は各々実施例１．
実施例２．実施例３および実施例４の収差図・ 第３図 餉４図 正弦条件 シ瞬瑳 陪　５図 第６図 ・１蟲　　　　　　　噛＋すａ　　　　　　　　１１１
”３１．１゜FIG. 1, FIG. 3, FIG. 5, and FIG. 7 each illustrate Example 1.
Example 2. FIG. 4 is a cross-sectional view of lenses of Example 3 and Example 4. FIG. 2, FIG. 4, FIG. 6, and FIG. 8 each show the results of Example 1.
Example 2. Aberration diagrams of Example 3 and Example 4. Figure 3. Figure 4. Sine condition. Figure 5. Figure 6. Figure 1.
”31.1°

Claims (1)

【特許請求の範囲】 物体側から順に、負メニスカスレンズ（第ルンズ）と正
メニスカスレンズ（第２レンズ）との接合レンズである
第１収束レンズ群、両凹負レンズ（第３レンズ）、およ
び１枚又は２枚の正レンズからなる第２収束レンズ群で
構成されており、次の各条件を満足する３群４枚又は４
群５枚構成の性能良好でコンパクトなビハインド絞り用
レンズ。 （１）　０．９０　＜　ｆ　／　ｆ、　、＜１．５０（
２）　１．６００　＜　（シ、−シ２）／（シ、／ｎ１
−シ２／ｎ２）（３）　１．５５０　＜　ｆ／ｎ、　Ｉ
　ｆ４．５１　＜１．７００　　、　　ｆ４．ｓ＜０（
４）　２．００　＜ｆ／ｆ、　　＜２．８０（５）　０
．−３０　＜　ｆｉｚ／　ｌ　ｆ＋　１　＜０．６５　
　、　　　ｆ４＜０（６）　０．９０　＜　ｆ、、／　
Ｉ　ｆ、　ｌ　＜１．５０　　、　　ｆ、、　＜０−　
但し ｆ　：全系の合成焦点距離 ｆエ　：第１収束レンズ群の合成焦点距離ν２．ν２　
：各々第ルンズ、第２レンズのア・ノベ数 ｎ、、　ｎ２ｇ　ｎｌ　　：各々第ルンズ、第２レンズ
、第３レンズのｄ−１ｉｎｅに対する屈折率ｆ４１．：
第３レンズの焦点距離 ｆｌ：第ルンズの物体側の面の焦点距離ｆ４：第３レン
ズの物体側の面の焦点距離ｆ、：第３レンズの像側の面
の焦点距離ｆ□　：第２収束レンズ群の最も物体側の面
の焦点距離 ｆ□２　：第２収束レンズ群の最も像側の面の焦点距離[Claims] In order from the object side, a first convergent lens group which is a cemented lens of a negative meniscus lens (first lens) and a positive meniscus lens (second lens), a biconcave negative lens (third lens), and It is composed of a second converging lens group consisting of one or two positive lenses, and has four or four lenses in three groups that satisfy the following conditions.
A compact, high-performance behind-the-diaphragm lens with a 5-element group configuration. (1) 0.90 < f / f, , < 1.50 (
2) 1.600 < (shi, -shi2)/(shi, /n1
-shi2/n2) (3) 1.550 < f/n, I
f4.51 <1.700, f4. s<0(
4) 2.00 <f/f, <2.80(5) 0
．． −30 < fiz/ l f+ 1 <0.65
, f4<0(6) 0.90<f,,/
If, l <1.50, f,, <0-
However, f: Composite focal length of the entire system f: Composite focal length of the first converging lens group ν2. ν2
: A novel number n of the 1st lens and the 2nd lens, respectively, n2g nl : The refractive index f41 for d-1ine of the 1st lens, the 2nd lens, and the 3rd lens, respectively. :
Focal length fl of the third lens: Focal length f4 of the object side surface of the third lens: Focal length f of the object side surface of the third lens: Focal length f of the image side surface of the third lens: Second Focal length of the surface closest to the object side of the converging lens group f□2: Focal length of the surface closest to the image side of the second converging lens group
JP4852382A 1982-03-26 1982-03-26 Behind-aperture lens Pending JPS58166314A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4852382A JPS58166314A (en) 1982-03-26 1982-03-26 Behind-aperture lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4852382A JPS58166314A (en) 1982-03-26 1982-03-26 Behind-aperture lens

Publications (1)

Publication Number Publication Date
JPS58166314A true JPS58166314A (en) 1983-10-01

Family

ID=12805715

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4852382A Pending JPS58166314A (en) 1982-03-26 1982-03-26 Behind-aperture lens

Country Status (1)

Country Link
JP (1) JPS58166314A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5161065A (en) * 1990-04-25 1992-11-03 Nikon Corporation Behind stop wide angle lens system
JPH05241068A (en) * 1991-10-12 1993-09-21 Leica Camera Gmbh Triplet type photographic objective lens
JP2011175198A (en) * 2010-02-25 2011-09-08 Ricoh Co Ltd Imaging lens, twin stereoscopic camera and distance measurement device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5161065A (en) * 1990-04-25 1992-11-03 Nikon Corporation Behind stop wide angle lens system
JPH05241068A (en) * 1991-10-12 1993-09-21 Leica Camera Gmbh Triplet type photographic objective lens
JP2588671B2 (en) * 1991-10-12 1997-03-05 ライカ カメラ ゲゼルシャフト ミット ベシュレンクテル ハフツング Triplet type photographic objective lens
JP2011175198A (en) * 2010-02-25 2011-09-08 Ricoh Co Ltd Imaging lens, twin stereoscopic camera and distance measurement device

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